Method for network controlled access selection

ABSTRACT

The invention provides an Access Selection Server (ASS) and a method for the same. The invention also provides a User Equipment (UE). The Access Selection Server (ASS) comprises storing means and software and is adapted for location in a communication network comprising at least one User Equipment (UE) and communication nodes. The ASS is also arranged to store information of all accesses for each UE in the communication network and information of overall load status of the communication network in the storing means by means of collecting information through interactions with the communication nodes, the UE and an Access Selection Server subscriber Data Base (ASS DB). The ASS is further arranged to communicate control messages, based on the stored information, from the ASS to the UE, thereby enabling control of multiple UE-accesses from the ASS.

TECHNICAL FIELD

The invention relates to an Access Selection Server (ASS) according tothe preamble of claim 1 and a method for an Access Selection Server(ASS) according to the preamble of claim 19. The invention furtherrelates to a User Equipment (UE) according to the preamble of claim 37.

BACKGROUND

Third generation mobile systems (3G), based on WCDMA (Wideband CodeDivision Multiple Access) radio access technology, are being deployed ona broad scale all around the world. However, as user and operatorrequirements and expectations will continue to evolve a new phase in theproject called 3^(rd) Generation Partnership Project (3GPP) has startedto consider the next major steps in the evolution of the 3G standard.The terminals used in the network are having more functions integratedwhich means that an increasing number of access types such as e.g. LTE(Long Term Evolution), WiMAX (Worldwide Interoperability for MicrowaveAccess) and WLAN (Wireless Local Area Network) and new services such asVoice over IP (VoIP) or IP-TV are added to the terminal. This has theimplication that there is a need for support from the network to guidethe terminal regarding which access to select. The terminal ishenceforth in the description and claims called a User Equipment, UE.

In the technical specification 3GPP TS 23.203 v7.3.0,release 7,a newarchitecture for Policy and Charging Control (PCC) is introduced and thedifferent functions are specified. The PCC architecture is illustratedin FIG. 1. The functions in FIG. 1 are, according to this specification,defined as follows.

The main parts of the PCC architecture consists of an ApplicationFunction (AF), 101, a PCRF (Policy and Charging Rules Function), 103, aSubscription Profile Repository (SPR), 107 and a PCEF (Policy andCharging Enforcement Function), 105. These parts are shown in FIG. 1.The PCC also includes an Online Charging System (OCS) connected to thePCEF through a reference point Gy and an Offline Charging System (OFCS)connected to the PCEF through a reference point Gz. The OCS and OFCS arenot shown in FIG. 1 as they are not of primary interest for theinvention.

The Application Function (AF) 101 is an element offering applicationsthe possibility to request resource allocation, via the PCC, in thenetwork such as e.g. Universal Mobile Telecommunication System (UMTS)Packet Switched (PS) domain or General Packet Radio Service (GPRS)domain resources. One example of an application function is a P-CSCF(Proxy—Call Session Control Function). The P-CSCF is a SIP (SessionInitiated Protocol) proxy server which is the first point of contact foran IMS (IP Multimedia Subsystem) User Equipment.

The AF 101 use an Rx reference point 102 to provide session informationto the PCRF (Policy and Charging Rules Function) 103. The signallingflow between the AF 101 and the PCRF 103 through the Rx reference point102 is specified in 3GPP TS 29.213 v7.0.0. More detailed informationregarding the PCC over the Rx reference point is specified in 3GPP TS29.214 v7.0.0.

The PCRF 103 is a functional element that encompasses policy controldecision and flow based charging control functionalities. These 2functionalities are the heritage of the 3GPP release 6 logical entitiesPDF (Policy Decision Function) and CRF (Charging Rules Function)respectively. The PCRF provides network control regarding the servicedata flow detection, gating, QoS (Quality of Service) and flow basedcharging (except credit management) towards the PCEF (Policy andCharging Enforcement Function). The PCRF receives session and mediarelated information from the AF and informs the AF of traffic planeevents.

A Gx reference point 104 is located between the PCRF and the PCEF. TheGx reference point is used for provisioning and removal of PCC rulesfrom the PCRF to the PCEF and the transmission of traffic plane eventsfrom the PCEF to the PCRF. The stage 2 level requirements for the Gxreference point are defined in 3GPP TS 23.203 v7.3.0, release 7.

Signalling flows between the PCRF and the PCEF through the Gx point 104is specified in 3GPP TS 29.213 v7.0.0. More detailed informationregarding the PCC over the Gx reference point is specified in 3GPP TS29.212 v7.0.0.

The PCC contains a number of rules defining how to treat received datapackages. The purpose of a PCC rule is to:

-   -   Detect a packet belonging to a service data flow.        -   The service data flow filters within the PCC rule are used            for the selection of downlink IP-CAN (Internet Protocol            Connectivity Access Network) bearers. An IP-CAN bearer is an            information transmission path of defined capacity, delay,            bit error rate e.t.c. When using GPRS (General Packet Radio            Service) the IP-Connectivity Access Network (IP-CAN) bearers            are provided by Packet Data Protocol (PDP) contexts.        -   The service data flow filters within the PCC rule are used            for the enforcement that uplink IP flows are transported in            the correct CIP-AN bearer.    -   Identify the service the service data flow contributes to.    -   Provide applicable charging parameters for a service data flow.    -   Provide policy control for a service data flow.

The PCEF shall select a PCC rule for each received packet by evaluatingreceived packets against service data flow filters of PCC rules in theorder of the precedence of the PCC rules. When a packet matches aservice data flow filter, the packet matching process for that packet iscompleted, and the PCC rule for that filter shall be applied.

There are two types of procedures for activation of rules:

-   -   Rules activated at IP-CAN        establishment/modification/deactivation.    -   Rules activated/modified/deactivated at application session        setup/modification/deactivation.

A PCC rule consists of:

-   -   a rule name;    -   service identifier;    -   service data flow filter(s);    -   gate status;    -   QoS parameters;    -   charging key (i.e. rating group);    -   other charging parameters.

The PCEF is the functional element that encompasses policy enforcementand flow based charging functionalities. These 2 functionalities are theheritage of the 3GPP release 6 logical entities PEP (Policy EnforcementPoint) and TPF (Traffic Plane Function) respectively. This functionalentity is located at a Gateway 106 e.g. a Gateway GPRS Support Node(GGSN) in the GPRS (General Packet Radio Service) case. It providescontrol over the user plane traffic handling at the Gateway and itsQuality of Service (QoS), and provides service data flow detection andcounting as well as online and offline charging interactions.

For a service data flow that is under policy control the PCEF shallallow the service data flow to pass through the Gateway 106 if and onlyif the corresponding gate is open.

The Subscription Profile Repository function (SPR) 107 contains allsubscriber/subscription related information needed forsubscription-based policies and bearer level charging rules by the PCRF.The SPR may be combined with other databases in the operator's network.

The Sp reference point 108, between the SPR and the PCRF, allows theSubscription Profile Repository (SPR) to provide subscription-basedinput to the PCRF. The Sp reference point allows the PCRF to requestsubscription information related to bearer level policies from the SPRbased on subscriber ID. The subscriber ID can e.g. be IMSI(International Mobile Subscriber Identity). The reference point allowsthe SPR to notify the PCRF when the subscription information has beenchanged if the PCRF has requested such notifications.

In the 3GPP TS 23.203 v7.3.0, release 7, PCC architecture the PCRF hasgot a passive role in the access selection procedures. At IP-CANestablishment the Radio Access Technology (RAT) type is sent to thePCRF. The PCRF is able to reject the IP-CAN establishment e.g. in casethe RAT type is not according to the user's profile. The PCRF has noactive role in the selection of the access type. The decision of whataccess to use within one access type (e.g. 2.5 G vs. 3G) is typicallycontrolled via interactions between the UE and the radio network. Thedecision, about which access types to select, if there are multipleaccess types (e.g. WLAN and WCDMA) available, is today mainly controlledby the UE.

With the existing solution there is no mechanism available that canenable control from the network regarding which access type to select.The selection of access type is primarily controlled by the UE.

This means that there are limited possibilities in prior art solutionsof today for the network provider to control the access selection andguide the user to a certain access e.g. in order to:

-   -   Optimize the network load by suggesting the UEs to use the most        cost effective access type when the UE is in e.g. a hot spot        area.    -   Control that the UE uses the access type that is most        appropriate for the application.        The current PCC architecture can handle several parallel IP-CANS        for the same UE but the architecture demands that each IP-CAN is        treated individually. This means that there is no place in the        network with a full control of all active accesses for one user.        This also means that there are limited possibilities for the        network to orchestrate between the different accesses.

SUMMARY

The invention intends to remove the above mentioned deficiencies withprior art solutions and to find an improved solution to control multiaccesses for a User Equipment (UE) in a communication network. This isaccomplished by providing:

-   -   An Access Selection Server (ASS) comprising storing means and        software. The ASS is adapted for location in a communication        network comprising at least one User Equipment (UE) and        communication nodes wherein the ASS is arranged to allow each UE        to have multiple accesses to at least one Packet Data Network        Gateway (PDN GW) being part of the communication network, each        access comprising one IP-session. The ASS is also arranged to        store information of all accesses for each UE in the        communication network and information of overall load status of        the communication network in the storing means by means of        collecting information through interactions with the        communication nodes, the UE and an Access Selection Server        subscriber Data Base (ASS DB). The ASS is further arranged for        communicating control messages, based on the stored information,        from the ASS to the UE, thereby enabling control of multiple        UE-accesses from the ASS.    -   A method for an Access Selection Server (ASS) comprising storing        means and software. The ASS is located in a communication        network, the communication network comprising at least one User        Equipment (UE) and communication nodes wherein the ASS allows        each UE to have multiple accesses to at least one Packet Data        Network Gateway (PDN GW) being part of the communication        network, each access comprising one IP-session. The ASS further        stores information of all accesses for each UE in the        communication network and information of overall load status of        the communication network in the storing means by collecting        information through interactions with the communication nodes,        the UE and an Access Selection Server subscriber Data Base (ASS        DB). The ASS also communicates control messages, based on the        stored information, from the ASS to the UE, thereby enabling        control of multiple UE-accesses from the ASS.    -   A User Equipment (UE) arranged to interact with a communication        network wherein the UE comprises an ASS-function and wherein the        UE further is arranged to communicate through an IP-based        interface with an ASS. The ASS function in the UE is arranged to        handle requests from the ASS to perform activation of new        accesses and/or modification or deactivation of existing        accesses.    -   A communication system comprising an Access Selection Server        (ASS).

As mentioned above the ASS is arranged for communicating controlmessages, based on the stored information, from the ASS to the UE,thereby enabling control of multiple UE-accesses from the ASS. By theexpression “control of multiple UE-accesses from the ASS” used above ismeant that the ASS provides the UE with information for access selectionand suggests a suitable access and that the final decision on accessselection is performed by the ASS function in the UE. This definition of“control of multiple UE-accesses from the ASS” is henceforth used in thedescription and claims.

The UE is typically a mobile phone but can also be any types ofterminals such as lap tops, smart phones or PDAs (Personal DigitalAssistant). The UE can also be split into two parts as e.g. a mobilephone part and a modem part.

The PCRF, the AF, the PDN GW and the NMS are examples of communicationnodes in a 3GPP (3^(rd) Generation Partnership Project) environmentinteracting with the ASS. The ASS can interact with one or several ofthese communication nodes. However the invention is also suitable forcommunication networks based on and/or evolved from the 3GPPcommunication network or other communication networks, such as non-3GPPcommunication networks, where the ASS will interact with othercommunication nodes.

The invention provides an ASS, a corresponding method and acommunication system having the advantage of providing increased accessselection control from the communication network. The invention alsoprovides a UE being equipped to interact with the ASS.

The inventive ASS will continuously be updated from the PCRF of allcurrent active IP-CANS and corresponding active access types. The ASS isalso optionally updated from the UE of e.g. available passive accessesand geographical location information for the UEs. Normally the ASSreceives information concerning geographical location of the UE from thePCRF. The information about available passive accesses is communicatedfrom the UE in case of direct access selection, described in associationwith FIG. 3.

The invention also has the advantage that the AF during session setupcan request help from the ASS about what access and Radio AccessTechnology (RAT) to run this service on. The ASS has information aboutwhich Radio Access Technologies (RAT) that currently are active for thesame UE. The ASS will also receive knowledge of the overall load statusof the communication network from the Network Management System (NMS)and information about the most suitable mapping between services andaccess types accomplished by operator configurable rules. The mappingmay be based on e.g. time of day, service type or location. Theinteraction between the AF, the ASS and the ASS function in the UE willguide the UE on what access to use for the specific service e.g. the UEmay select a new access to run the service on. A Proxy-Call SessionControl Function (P-CSCF) is an example of an AF.

The invention comprises a number of new or modified components andfunctions compared to the current Policy and Charging Control (PCC) asdefined in Specification 3GPP TS 23.203 v7.3.0 release 7. Here “new” or“modified” means that the components and functions referred to are notcomprised in the prior art but are specific for the invention. These newor modified components and functions comprise:

-   -   A new, logic control function included in the ASS. The ASS may        for instance be incorporated into the PCRF node or form a        separate ASS-node. The ASS will have control of all accesses for        the UE, with information concerning e.g. current load on the        network, geographic location as cell identification, service        identification specifying what type of service that is being        established and current Radio Access Technology (RAT). These        informations are examples of ASS access information. The ASS        will communicate access selection criteria to the ASS function        in the UE. The criteria may be based on e.g. communication        network load, service type, active access types for the UE,        location, and time of day.    -   A new ASS function in the UE. The ASS function in the UE will        e.g. perform activation of new accesses and/or modification or        deactivation of existing accesses based on requests from the ASS        to handle the ASS functionalities in the UE. This is described        further in the detailed description.    -   A new reference point Rx1 between the AF and the ASS designated        Rx1 in FIG. 2. The interface corresponding to this new reference        point Rx1 will be used during IP-session activation/modification        to inform the ASS in order to enable the ASS to suggest        activation/modification of accesses and guide the UE how to move        IP-sessions between different accesses for the UE. This new        reference point can be used for direct communication between the        AF and the ASS when the ASS is a separate node. An alternative        to this solution, which is described under an extended PCRF        function below, is that the AF communicates via the Rx reference        point, the PCRF and an Rx2 reference point to the ASS, thus        making the Rx1 reference point not required. The Rx2 reference        point is described below. The Rx1-reference point, being an        Rx-reference point as defined in 3GPP TS 29.213 v7.0.0 and 3GPP        TS 29.214 v7.0.0, is arranged between the ASS and the AF and        enables the AF to communicate a request, for updating the        multi-access policy rules in the UE due to AF session        establishment/modification/deactivation, to the ASS. The        invention is not restricted to the specifications 3GPP TS 29.213        v7.0.0 and 3GPP TS 29.214 v7.0.0 but the Rx reference point may        also be defined in any future revised 3GPP specifications, i.e.        any future specification being based on the above mentioned        specification(s) or any new specification comprising the Rx        reference point. The Rx1 reference point is further arranged to        handle communication between the ASS and AF to inform the ASS of        activations and modifications of IP-sessions. The information        transferred is also used to identify the session and the        service. Minor additions/modifications of the information        available in the Rx reference point according to 3GPP TS 29.213        v7.0.0 and 3GPP TS 29.214 v7.0.0 or according to any future        revised 3GPP specifications, i.e. any future specification being        based on the above mentioned specification(s) or any new        specification comprising the Rx reference point are within the        scope of the invention as long as the functions for the Rx1        reference point as described in the description and claims are        met.    -   A new reference point Rx2 between the PCRF and the ASS. The        interface corresponding to this new reference point is used to        transfer IP-session information about the IP sessions in the        PCRF e.g. active Radio Access Technology (RAT) and UE source IP        address to the ASS. The new reference point is an Rx or Gx        reference point or an aggregation of the Rx and Gx reference        points. The Rx and Gx reference points are defined in 3GPP TS        29.213 v7.0.0, 3GPP TS 29.214 v7.0.0 and 3GPP TS 29.212 v7.0.0.        The invention is not restricted to the specifications 3GPP TS        29.213 v7.0.0, 3GPP TS 29.214 v7.0.0 and 3GPP TS 29.212 v7.0.0        but the Rx and Gx reference points may also be defined in any        future revised 3GPP specifications, i.e. any future        specification being based on the above mentioned        specification(s) or any new specification comprising the Rx and        Gx reference points. Minor additions/modifications of the        information available in the Rx and Gx reference points        according to the specifications 3GPP TS 29.213 v7.0.0, 3GPP TS        29.214 v7.0.0 and 3GPP TS 29.212 v7.0.0 or according to any        future revised 3GPP specifications, i.e. any future        specification being based on the above mentioned        specification(s) or any new specification comprising the Rx and        Gx reference points are within the scope of the invention as        long as the functions for the Rx2 reference point as described        in the description and claims are met. This new reference point        is designated Rx2 in FIG. 2. When the AF communicates via the Rx        reference point, the PCRF and the Rx2 reference point with the        ASS, thus making the Rx1 reference point not required, the Rx2        reference point has to be extended with the functionalities        described for the Rx1 reference point.    -   Extending the PCRF with new procedures for two new messages. In        the first message the PCRF reports session information, via the        reference point Rx2, to the ASS about RAT and IP address and        other possible session information stored in the PCRF session        data base such as e.g. geographical location of the UE, Roaming        status, UE information as e.g IMEISV (International Mobile        station Equipment Identity and Software) or IMEI (International        Mobile station Equipment Identity) and information regarding        IMSI (International Mobile Subscriber Identity). In the second        message the PCRF is arranged to receive acknowledgement from the        ASS of the activation, modification and deactivation of all        IP-CANS from the UE. The PCRF can also optionally communicate a        request, for updating the multi-access policy rules in the UE        due to AF session establishment/modification/deactivation, from        the AF to the ASS via the Rx2 reference point. In this case the        Rx1 reference point is not required and the information exchange        described for the Rx1 reference point will be communicated from        the AF through the Rx reference point, the PCRF and the Rx2        reference point to the ASS. Minor additions/modifications of the        information available in the Rx reference point according to        3GPP TS 29.213 v7.0.0 and 3GPP TS 29.214 v7.0.0 or according to        any future revised 3GPP specifications, i.e. any future        specification being based on the above mentioned        specification(s) or any new specification comprising the Rx        reference point are within the scope of the invention as long as        the functions for the communication between the AF and the PCRF        as described in the description and claims are met.    -   A new interface between the ASS function in the UE and the ASS.        The interface is an IP-based interface between the ASS function        in the UE and the ASS. The interface is used to transport        multi-access policy rules from the ASS to the ASS function in        the UE and optionally information from the ASS function in the        UE to the ASS regarding e.g. available passive accesses and        geographical location of the UE. The advantage by using this        IP-based interface is that a generic non-access specific        protocol can be used.

Here “aggregation” of the Rx and Gx reference points refers to thateither all the information available in both the Rx and Gx referencepoints are available in the new reference point Rx2 or that a part orparts of the information available at the Rx reference point and a partor parts of the information available at the Gx reference point areavailable at the new reference point Rx2.

The main advantages with the invention can be summarized as follows:

-   -   The invention will enable multi-access control from the        communication network. The communication network will have        control of all accesses activated for each UE. The total control        of all accesses for one UE will thus be available at one        location in the communication network. The communication network        will be able to suggest the UE to activate new accesses or move        sessions to another active access.    -   The communication network can use several criteria to control        the access selection e.g.        -   Load of the communication network        -   Type of service        -   Location        -   Time of day.    -   The invention may build from the existing Policy and Charging        Control (PCC) solution in 3GPP as defined in 3GPP TS 23.203        v7.3.0, release 7 or any future revised 3GPP specifications,        i.e. any future specification being based on the above mentioned        specification or any new specification comprising the PCC.        -   This enables a smooth introduction of the invention and            avoids unwanted interaction problems with the current PCC            implementations and overlapping functionality in the PCC.    -   Minor additions/modifications of the PCC according to the        specification 3GPP TS 23.203 v7.3.0, release 7 or according to        any future revised 3GPP specification, i.e. any future        specification being based on the above mentioned specification        or any new specification comprising the PCC are within the scope        of the invention as long as the functions of the invention as        described in the description and claims are met.

The invention is not restricted to 3GPP specifications, but also validfor specifications being identical to or similar to 3GPP. Examples ofsuch specifications are 3^(rd) Generation Partnership Project 2 (3GPP2)and Telecoms & Internet converged Services and Protocols for AdvancedNetworks (Tispan).

Further advantages are achieved by implementing one or several of thefeatures of the dependent claims which will be explained below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Schematically shows Policy and Charging Control (PCC) accordingto prior art.

FIG. 2 Schematically shows a block diagram of interactions between theAccess Selection Server (ASS) and other functions in a 3GPP environment.

FIG. 3 Illustrates examples of Access selection criteria.

FIG. 4 Schematically shows some embodiments for relations between theASS and the PCC.

FIG. 5 Schematically shows a logical view of multiple IP sessionscontrolled by one multi-access session.

FIG. 6 Schematically shows a deployment view of multiple IP sessions forone User Equipment (UE) controlled by one multi-access session.

FIG. 7 Schematically shows a signalling diagram for an IP-CANestablishment.

FIG. 8 Schematically shows a signalling diagram for change of access dueto AF session establishment with accesses A and B active.

FIG. 9 Schematically shows a signalling diagram for change of access dueto AF session establishment with access B active and access A activatedbased on request from the network.

FIG. 10 Schematically illustrates the method of the invention.

DETAILED DESCRIPTION

The invention will now be described in detail with reference to thedrawings and some examples of implementations of the invention.

FIG. 1 has already been described in relation to Background above.

FIG. 2 schematically shows a block diagram of interactions betweeninventive Access Selection Server (ASS) 201 and other functions in a3GPP environment. This is an embodiment where the ASS is adapted forlocation in a 3GPP network. It can also be adapted for location innon-3GPP communication networks. The ASS collects information about theload status of the communication network from a Network ManagementSystem (NMS) 202. An ASS subscriber DataBase (ASS DB) 203 in a 3GPPenvironment informs the ASS of Multi Access Control Policies such ase.g.:

-   -   Subscription related policies    -   Roaming/Access Agreements    -   User Preferences

The information between the ASS DB and the ASS is transferred through aninterface 217 when the ASS and the ASS DB are separate nodes as showne.g. in FIG. 4 b. When the ASS and the ASS DB are deployed in otherconfigurations as described in association with FIG. 4, the interface217 can be used, or existing interfaces between nodes or node-internalinterfaces can be adapted for including communication between the ASSand the ASS DB. The interface 217 can e.g. be a Lightweight DirectoryAccess Protocol (LDAP).

The information stored in storing means of the ASS DB is normallyprovided by the communication network operator but part of theinformation can be modified from the subscriber within operatorconfigured limits. The modification can e.g. be made via a Web GUI(Graphical User Interface). The ASS DB can, as is the case also for theASS, be adapted for 3GPP communication networks or non-3GPPcommunication networks. For non-3GPP communication networks the ASS DBcommunicates corresponding information to the ASS as described for the3GPP communication network above.

The subscription related policies in the ASS DB can e.g. be divided inPremium and Basic users with multi access policies like different accesstypes, classes of Quality of Service (QoS) or Best effort. Best effortis the lowest of all QoS traffic classes. If the guaranteed QoS cannotbe delivered, the bearer network delivers the QoS which can also becalled Best effort QoS.

An Application Function (AF) 204 communicates with a Policy and ChargingRules Function (PCRF) 206 via an Rx reference point 205. An SPR 207communicates with the PCRF via a reference point Sp 208 and the PCRFcommunicates with a PCEF 210 via a Gx reference point 209. All parts204-210 are part of the PCC architecture and are explained inassociation with FIG. 1.

One example of an AF function is a P-CSCF (Proxy—Call Session ControlFunction). In the case the IP-session is an IMS-session (Internetprotocol Multimedia Subsystem) the P-CSCF is part of the IMS core.

The PCEF 210 functional entity is located at a Packet Data NetworkGateway (PDN GW) 211 (e.g. Gateway GPRS Support Node, GGSN, in the GPRScase). It provides control over the user plane traffic handling at thePDN GW and its QoS, and provides service data flow detection andcounting as well as online and offline charging interactions. For aservice data flow that is under policy control the PCEF shall allow theservice data flow to pass through the PDN GW 211 if and only if thecorresponding gate is open.

The PDN GW is a general terminology for a gateway between a Packet DataNetwork (PDN) and any access specific network as e.g. a 3GPP or anon-3GPP communication network. Typical functionality of a PDN GWincludes:

-   -   Policy enforcement    -   Per-user based packet filtering (by e.g. deep packet inspection)    -   Charging support    -   Lawful Interception    -   UE IP address allocation    -   Packet screening

The PDN GW may for some access technologies or standardization bodies beintegrated with other core network nodes. In 3GPP the PDN GWfunctionality is located in the GGSN node and for 3GPP SystemArchitecture Evolution (SAE) the PDN GW functionality is a unique nodenamed PDN GW.

The UE 212 is connected via one or several IP-CANS 213, such as anetwork based on Radio Access Technology (RAT), to the PDN GW 211comprising the PCEF 210. The PDN GW 211 is also connected to the PCRFvia reference point Gx 209. The UE can also communicate with more thanone PDN GW each PDN GW having one or several IP-CAN connections with theUE. All these IP-CANS from the UE are henceforth called UE IP-CANS. Forclarity reasons FIG. 2 shows just one IP-CAN 213 and one PDN GW 211.

The UE, 212, arranged to interact with the communication network, isconnected to the ASS through an IP-based interface 214. The UE willinclude an ASS function comprising multi-access policy rules. Thesemulti-access policy rules can be of either a direct selection type or ofa selection type using a preference list as described in associationwith FIG. 3. The ASS function in the UE will, based on requests from theASS, handle the ASS functionalities in the UE as e.g. perform activationof new accesses and/or modification or deactivation of existing accessesaccording to the multi-access policy rules. The IP connection betweenthe ASS function in the UE and the ASS, through the IP-based interface214, will be established at activation of the default IP-CAN. This IPconnection is used to communicate access selection information betweenthe ASS function in the UE and the ASS. The ASS function in the UE cane.g. receive data concerning selection of Radio Access Technology. Otherexamples of such information communication is transport of multi-accesspolicy rules from the ASS to the ASS function in the UE and optionallyinformation from the ASS function in the UE to the ASS regarding e.g.available passive accesses and geographical location of the UE. Normallythe ASS receives information concerning geographical location of the UEfrom the PCRF. The information about available passive accesses iscommunicated from the ASS function in the UE in case of direct accessselection, described in association with FIG. 3.

The UE will inform the ASS from the ASS function in the UE, via theIP-based interface, 214, about access information, including IP sessioninformation, e.g. RAT type, on all active and passive accesses. Apassive access is an access possible for the UE to activate but that iscurrently not activated. Each access comprises one IP-session.

An alternative embodiment is to use an access specific interface insteadof the IP-based interface 214 for communication between the UE and ASS.An example of such an interface is GTP (GPRS Tunneling Protocol) for3GPP accesses. The information in the GTP protocol is transferred fromthe UE via the PDN GW 211, the reference point Gx 209, the PCRF 206 andan Rx2 reference point 216 to the ASS 201.

The Network Management System (NMS) 202 is a combination of hardware andsoftware used to monitor and administer a network. The ASS receivesinformation about load status for different Radio Access Technologieswithin the communication network from the NMS through a managementinterface 218. This interface can e.g. be a Simple Network ManagementProtocol (SNMP) defined by the Internet Engineering Task Force (IETF).The SNMP can e.g. initiate an alarm signal to the ASS when thecommunication network load exceeds a certain maximum-level and a clearsignal when the load is below a certain minimum-level. This is performedper access type and geographical area.

The invention comprises two new reference points Rx1, 215, and Rx2, 216.Rx1 is a new reference point between the AF and the ASS. The Rx1reference point is an option that can be used in the case the ASS is aseparate node. The interface corresponding to this new reference pointRx1 will be used during IP-session activation/modification to inform theASS in order to enable the ASS to suggest activation/modification ofaccesses and guide the UE how to move IP- sessions between differentaccesses for the UE. This new reference point can be used for directcommunication between the AF and the ASS when the ASS is a separatenode. An alternative to this solution, which is described under anextended PCRF function below, is that the AF communicates via the Rxreference point, the PCRF and the Rx2 reference point to the ASS, thusmaking the Rx1 reference point not required.

The Rx2 reference point is described below. The Rx1-reference point,being an Rx-reference point as defined in 3GPP TS 29.213 v7.0.0. and3GPP TS 29.214 v7.0.0, is arranged between the ASS and the AF andenables the AF to communicate a request, for updating the multi-accesspolicy rules in the UE due to AF sessionestablishment/modification/deactivation, to the ASS. The invention isnot restricted to the specifications 3GPP TS 29.213 v7.0.0 and 3GPP TS29.214 v7.0.0 but the Rx reference point may also be defined in anyfuture revised 3GPP specifications, i.e. any future specification beingbased on the above mentioned specification(s) or any new specificationcomprising the Rx reference point. The Rx1 reference point is furtherarranged to handle communication between the ASS and AF to inform theASS of activations and modifications of IP-sessions. The informationtransferred is also used to identify the session and the service. Minoradditions/modifications of the information available in the Rx referencepoint according to 3GPP TS 29.213 v7.0.0 and 3GPP TS 29.214 v7.0.0 oraccording to any future revised 3GPP specifications, i.e. any futurespecification being based on the above mentioned specification(s) or anynew specification comprising the Rx reference point are within the scopeof the invention as long as the functions for the Rx1 reference point asdescribed in the description and claims are met.

Rx2 is a new reference point between the PCRF and the ASS arranged tohandle communication between the ASS and the PCRF. The interfacecorresponding to this new reference point is used to transfer IP-sessioninformation about the IP sessions in the PCRF e.g. active Radio AccessTechnology (RAT) and UE source IP address to the ASS. The new referencepoint is an Rx or Gx reference point or an aggregation of the Rx and Gxreference points, these reference points being defined in 3GPP TS 29.213v7.0.0, 3GPP TS 29.214 v7.0.0 and 3GPP TS 29.212 v7.0.0. The inventionis not restricted to the specifications 3GPP TS 29.213 v7.0.0, 3GPP TS29.214 v7.0.0 and 3GPP TS 29.212 v7.0.0 but the Rx and Gx referencepoints may also be defined in any future revised 3GPP specifications,i.e. any future specification being based on the above mentionedspecification(s) or any new specification comprising the Rx and Gxreference points. Minor additions/modifications of the informationavailable in the Rx and Gx reference points according to thespecifications 3GPP TS 29.213 v7.0.0, 3GPP TS 29.214 v7.0.0 and 3GPP TS29.212 v7.0.0 or according to any future revised 3GPP specifications,i.e. any future specification being based on the above mentionedspecification(s) or any new specification comprising the Rx and Gxreference points are within the scope of the invention as long as thefunctions for the Rx2 reference point as described in the descriptionand claims are met. This new reference point is designated Rx2 in FIG.2. When the AF communicates via the Rx reference point, the PCRF and theRx2 reference point with the ASS, thus making the Rx1 reference pointnot required, the Rx2 reference point has to be extended with thefunctionalities described for the Rx1 reference point.

The PCRF 206 is extended with new procedures for two new messages. Inthe first message the PCRF reports session information, via thereference point Rx2, to the ASS about RAT and IP address and otherpossible session information stored in the PCRF session data base suchas e.g. geographical location of the UE, Roaming status, UE informationas e.g IMEISV (International Mobile station Equipment Identity andSoftware) or IMEI (International Mobile station Equipment Identity) andinformation regarding IMSI (International Mobile Subscriber Identity).In the second message the PCRF is arranged to receive acknowledgementfrom the ASS of the activation, modification and deactivation of all theUE IP-CANS 213. The PCRF can also optionally communicate a request, forupdating the multi-access policy rules in the UE due to AF sessionestablishment/modification/deactivation, from the AF to the ASS via theRx2 reference point. In this case the Rx1 reference point is notrequired and the information exchange described for the Rx1 referencepoint will be communicated from the AF through the Rx reference point,the PCRF and the Rx2 reference point to the ASS. Minoradditions/modifications of the information available in the Rx referencepoint according to 3GPP TS 29.213 v7.0.0 and 3GPP TS 29.214 v7.0.0 oraccording to any future revised 3GPP specifications, i.e. any futurespecification being based on the above mentioned specification(s) or anynew specification comprising the Rx reference point are within the scopeof the invention as long as the functions for the communication betweenthe AF and the PCRF as described in the description and claims are met.

When the Rx1 reference point is used between the AF or P-CSCF and theASS, the AF or P-CSCF has to be modified to communicate a request, forupdating the multi-access policy rules in the UE due to AF sessionestablishment/modification/deactivation, from the AF or P-CSCF to theASS via the Rx1 reference point. The request will contain informationabout the service type e.g. an ICSI (IMS Communication Service ID)and/or IARI (IMS Application Reference Identifier) from SIP (SessionInitiation Protocol) INVITE and information from a SDP (SessionDescription Protocol) in order to identify the service session. Thisrequest will be described more in association with FIG. 8.

The PCRF 206, the AF 204, the PDN GW 211 and the NMS 202 are examples ofcommunication nodes in a 3GPP (3^(rd) generation Partnership Project)communication network interacting with the ASS. However the invention isalso suitable for communication networks based on and/or evolved fromthe 3GPP communication network or other communication networks, such asnon-3GPP communication networks, where the ASS will interact with othercommunication nodes.

The ASS will use the information received as described above for a newlogic control function. The ASS may for instance be incorporated intothe PCRF node or form a separate ASS node. The ASS will have control ofall accesses for the UE and have all ASS access information available.The ASS will communicate control messages including e.g. accessselection criteria to the ASS function in the UE based on theinformation stored in the ASS storing means. The criteria may be basedon communication network load, service type, active access types for theUE, location and time of day.

The ASS and the ASS DB will comprise any type of conventional storingmeans well known to the skilled person.

The ASS may be integrated with both the PCRF and the AF (e.g. P-CSCF)into one logical node. Further integration examples are described inassociation with FIG. 4.

When the ASS and the PCRF are integrated in the same node the Rx2interface or a node-internal interface can be used for communicationbetween the PCRF and the ASS.

There is typically only one ASS per Public Land Mobile Network (PLMN).If there are more than one ASS, the ASS can be addressed with a useridentification as e.g. International Mobile Subscriber Identity (IMSI).

FIG. 3 shows how the ASS 301 will be able to communicate either a directaccess selection criterion 303 or an access selection criterion definedin a preference list 304 to the UE 302 via the IP-based interface 305.In the example of FIG. 3 the direct access selection criterion is thatfor the service Voice, the RAT type WLAN is to be used. If thepreference list 304 is used, the example of FIG. 3 shows that if theservice is Voice and the location Home, WLAN (Wireless Local AreaNetwork) shall have priority 1 and UTRAN (Universal Terrestial RadioAccess Network) priority 2. If however the location is PLMN, UTRANreceives first priority and WLAN second. Other parameters can also beincluded in the preference list as e.g. load, time of the day e.t.c. Thedirect selection is easy to handle in the UE but requires moresignalling. The preference list selection requires more sophisticatedprocessing in the UE but gives the advantage of easier signallingprocedures. Both solutions are possible within the scope of theinvention. One embodiment of the invention can have direct selection andanother embodiment the preference list embodiment. A further possibilityis that a third embodiment has both selection alternatives available anda choice of which type to use is made by e.g. a network operator. Theaccess selection criteria are included in the ASS software beingarranged to be communicated to the UE through the IP based interface305, thus establishing a control of the UE from the ASS. The ASSfunction in the UE must be equipped for the selection embodiment used.In the case when the direct access selection criterion is usedinformation of available passive accesses is communicated to the ASSfrom the ASS function in the UE.

FIG. 4 shows some alternatives for ASS relations with the PCC. In FIG. 4a the AF 401 and a SPR 403 are connected to a PCRF 402. The ASS 404 isintegrated with the PCRF 402 and the ASS DB 405 is integrated with theSPR 403. An advantage with this solution is that no additional node isintroduced. The PCRF 402 and the SPR 403 have to be adapted for thedeployment. The integration means that the ASS/PCRF is integrated intoone logical node and the ASS DB/SPR is integrated into another logicalnode. In FIG. 4 b, which is according to the FIG. 2 architecture, the AF406 and the SPR 408 are connected to the PCRF 407. The ASS DB 410 isconnected to the ASS 409 and the ASS is connected to the PCRF 407. Anadvantage with this solution is that it has minimal impact on the PCRFand the SPR. However an additional node is introduced.

Other possibilities for integration embodiments of the invention notshown in FIG. 4 are e.g. that the ASS/ASS DB or ASS/ASS DB/PCRF orASS/PCRF/SPR or ASS/PCRF/SPR/ASS DB are integrated into one logicalnode. Another example of integration is that the ASS, the ASS DB and theSPR are integrated in one PCRF A and that the ASS integrated in the PCRFA also communicates with a geographically separated PCRF B. The PCRF-Acan also communicate with several, from the PCRF-A, geographicallyseparated PCRFs. The examples with several PCRFs to one ASS areapplicable in the case when one UE has IP-CANS connected to severalPCRFs. In all the integration examples the AF, as e.g. the P-CSCF, canalso be included in the integration. Other integration combinations ofthe ASS with communication nodes are also possible within the scope ofthe invention.

As mentioned in association with the description of FIG. 2 the P-CSCF isone example of an AF function. The P-CSCF is normally not affected bythe introduction of the ASS and communicates through the Rx referencepoint with the PCRF. This is the situation if the ASS is integrated intoone logical node with the PCRF or with the PCRF and further nodes, suchas the AF, and normally also when the ASS and PCRF are separate logicalnodes. Minor additions/modifications of the information available in theRx reference point according to 3GPP TS 29.213 v7.0.0 and 3GPP TS 29.214v7.0.0 or according to any future revised 3GPP specifications, i.e. anyfuture specification being based on the above mentioned specification(s)or any new specification comprising the Rx reference point are withinthe scope of the invention as long as the functions for thecommunication between the P-CSCF and the PCRF as described in thedescription and claims are met. When the ASS is a separate logical nodethere is however the additional possibility that the P-CSCF is modifiedto communicate a request to the ASS through the new reference point Rx1for activation of access selection.

The ASS function in the UE will e.g. perform activation of new accessesand/or modification or deactivation of existing accesses based onrequests from the ASS to handle the ASS functionalities in the UE. TheASS function in the UE will also be adapted for one or more of:

-   -   informing the ASS about available passive accesses for the UE        and/or geographical location information for the UE.    -   receiving data concerning selection of a Radio Access Technology    -   communicating a request for an IP-CAN establishment    -   initiating for SIP invite/reinvite as will be described in        association with FIGS. 7-9.

The ASS function in the UE can e.g. be arranged as part of the UEhardware/software or as a separate hardware/software module by anyconventional means well known to the skilled person. The ASS function inthe UE also communicates with other resources in the UE as e.g, an IMSfunction including a SIP client software module and/or accessestablishment resources.

The invention will now be further described from a logical anddeployment view and with use cases.

FIG. 5 shows an example where an UE A, has one multi-access session 501controlling two IP sessions 502 and 503 i.e. one for access A and onefor access B. The IP sessions are equal to the prior art IP sessionavailable in the PCRF. The IP session contains information about e.g.the current IP-CAN concerning Radio Access Technology (RAT) and sourceaddress of the UE. A purpose of the invention is to create a newmulti-access session with information about all currently activeaccesses for one UE, i.e. in this case IP sessions A and B for the UE A.When the IP session is started default bearers 504 and 505, within theaccess IP-CAN, are selected. During the session, one or severaldedicated bearers, 506-509 can be added.

FIG. 6 shows a possible deployment view with PCRF A and B, 601 and 602,based on the existing PCRF nodes. The UE A has two IP-CAN accesses A andB, access A connected to the PCRF A, 601, and access B connected to thePCRF B, 602. The ASS, 603, has a multi -access session 604 for the UE A.The multi-access session receives information from the PCRF A and Babout the IP sessions e.g. RAT type and UE source address, thuscontrolling the two IP sessions. The new reference point Rx2, 605, islocated between the PCRF and the ASS as described above. When the IPsession is started default bearers 606 and 607, within the accessIP-CAN, are selected. During the session, one or several dedicatedbearers, 608-611 can be added. In the embodiment of FIG. 6 the twoaccesses are in different PCRFs. In other embodiments the two accessescan be in the same PCRF.

At IP-CAN establishment between the UE and the PDN GW, e.g. when the UEis turned on, or, at modification of the IP-CAN, the ASS continuouslygets updated with the current access types that are active for the UE.This is illustrated in the signalling flow diagram in FIG. 7 comprisingthe UE 701, a GGSN A 702, a GGSN B 703, a PCRF A 704, a PCRF B 705 andthe ASS 706. The use case shows how the ASS 706 continuously gets ASSaccess information. In this case there are two radio accessessimultaneously (A and B) for the same UE 701. The use case shows a GPRSapplication, thus the PDN GW in this case is a Gateway GPRS Support Node(GGSN). The different messages 1-10 in the establishment of two IP-CANScomprise the following activities.

-   1. A request for IP-CAN establishment is sent to a GGSN A 702 from    the UE and the ASS function in the UE is informed of the new access.-   2. A request for PCC rules is sent from the GGSN A to a PCRF A 704    via the Gx reference point using message CCR (Create Charging Rule),    this message being defined in 3GPP TS 29.212 v7.0.0 chapter 5.6.2    and future revisions of this specification or future specifications    being based on this specification.-   3. The PCRF A reports session information, via the reference point    Rx2, to the ASS 706 about RAT and IP address and other possible    session information stored in the PCRF A session data base such as    e.g. geographical location of the UE, Roaming status, UE information    as e.g IMEISV (International Mobile station Equipment Identity and    Software) or IMEI (International Mobile station Equipment Identity)    and information regarding IMSI (International Mobile Subscriber    Identity). The ASS downloads Multi Access Control Policies for the    subscriber from the ASS DB and checks if the request is valid.-   4. The ASS acknowledges the starting up of the IP-CAN to the PCRF A.-   5. The PCRF A downloads PCC rules to the GGSN A and the GGSN A    acknowledges the IP-CAN establishment to the UE.

Messages 1-5 show how the ASS receives ASS access information about e.g.the currently used RAT type for the UE and the UE source IP address.Messages 3 and 4 are not comprised in prior art but are specific for theinvention. Hence message 3 and 4 are new messages but the other messagesexist in the current PCC standard, as defined in 3GPP TS 23.203 v7.3.0.

Messages 6-10 shows the same procedure for access B.

The following two use cases, illustrated in FIGS. 8 and 9, show how anaccess can be changed during session set up. These two use cases showhow the UE starts an IP session setup on an access B, here exemplifiedwith an IMS (IP Multimedia Subsystem) session, and during session setup,based on info from the ASS, moves the session to another RAT type(Access A). The IMS session is moved to an access A. The interactionbetween the ASS function in the UE, the P-CSCF and the ASS is describedin FIG. 8. The IMS session can e.g. be Multi Media Telephony, includingVoice over IP (VoIP), or IP-TV.

Two alternatives are shown: One when the new access is already activeand another when the UE, based on input from the network, activates anew, not active, RAT type.The signalling flow diagram of FIG. 8 comprises the UE 801, the ASS 802,the P-CSCF 803 and a PDN 804. FIG. 8 illustrates the situation when bothaccesses A and B are active i.e. two IP-sessions are established. SIPsignalling (Session Initiation Protocol), has started on access B. SIPis an IETF standard (Internet Engineering Task Force) used by 3GPP as asignalling protocol and permanent element of the IMS architecture. Theprocedure is described in activity steps 1-12 as follows:

-   1. A SIP INVITE message is initiated from the ASS function in the UE    801 and sent to the other end of the end-to-end SIP session via the    PDN 804 on the default bearer for access B. This signalling process    uses an offer/answer model with the Session Description Protocol    (SDP) as defined in IETF RFC 3264 and the IMS Communication Service    Identifier (ICSI) and/or IMS Application Reference Identifier (IARI)    as defined in 3GPP TS 24.229 chapter 7.2A.8 and 7.2A.9 and future    revisions of these two specification or future specifications being    based on these two specification. The ICSI and/or IARI is used to    identify the type of service-   2.A SIP 200 OK message is sent from the other end of the end-to-end    SIP session via the PDN to the P-CSCF 803.-   3. After the SDP offer/answer procedure, the P-CSCF will communicate    a request, for updating the multi-access policy rules in the UE due    to AF session establishment/modification/deactivation to the ASS 802    via the reference point Rx1. The request will contain information    about the service type e.g. the ICSI and/or IARI from SIP INVITE and    information from the SDP in order to identify the service session.-   4. The ASS will analyze what is the best access type based on the    SDP/ICSI/IARI parameters, including one or several of these    parameters, currently active access types for this UE, location and    network load. The ASS has information about current access types for    this UE .The ASS decides to move the SIP session to access type A.-   5. An ASS update message is sent to the ASS function in the UE with    a request that this IMS session shall be moved to the access A.-   6.The ASS function in the UE informs an IMS function in the UE that    media for this service shall be sent on the access A. The IMS    function in the UE handles e.g. SIP signalling and is interacting    with the ASS function in the UE.-   7.A successful response message is sent to the P-CSCF via the ASS    and the Rx1 reference point.-   8. A SIP 200 OK message is forwarded to the UE from the P-CSCF.-   9. The IMS function in the UE will, based on info from the ASS    function in the UE, move the session to the access A by sending a    SIP REINVITE message to the P-CSCF with the SDP for the access A in    order to confirm that the change to the access A has been performed.-   10. A SIP REINVITE message is forwarded to the other end of the    end-to-end session via the PDN.-   11,12. A SIP 200 OK message is received from the other end of the    end-to-end session via the PDN and forwarded to the P-CSCF and the    UE.

Media transfer can now start on the new access A.

The signalling flow diagram of FIG. 9 comprises the UE 901, the ASS 902,the P-CSCF 903 and the PDN 904. FIG. 9 illustrates the situation when anaccess B is active, i.e. one IP-session is established. SIP signallinghas started on the access B. The procedure is described in activitysteps 1-12 as follows.

-   1. A SIP INVITE message is initiated from the ASS function in the UE    901 to the other end of the end-to-end SIP session via the PDN 904    on the default bearer for the access B. This signalling process uses    an offer/answer model with the Session Description Protocol (SDP) as    defined in IETF RFC 3264 and the IMS Communication Service    Identifier (ICSI) and/or IMS Application Reference Identifier (IARI)    as defined in 3GPP TS 24.229 chapter 7.2A.8 and 7.2A.9 and future    revisions of these two specification or future specifications being    based on these two specification. The ICSI and/or IARI is used to    identify the type of service.-   2. A SIP 200 OK message is sent from the other end of the end-to-end    SIP session via the PDN to the P-CSCF 903.-   3. After the SDP offer/answer procedure, the P-CSCF will communicate    a request, for updating the multi-access policy rules in the UE due    to AF session establishment/modification/deactivation to the ASS 802    via the reference point Rx1. The request will contain information    about the service type e.g. the ICSI and/or IARI from SIP INVITE and    information from the SDP in order to identify the service session.-   4 & 5. The ASS will analyze what is the best access type based on    the SDP/ICSI/IARI parameters, including one or several of these    parameters, currently active access types for this UE, location and    network load. The ASS has information about current access types for    this UE. The ASS decides that this session, if possible, should be    handled on a RAT type A. There are two options how this can be    communicated between the ASS and the ASS function in the UE; the    direct access selection or the preference list selection as    described in association with FIG. 3. A prerequisite for direct    selection is that the ASS function in the UE has informed the ASS of    which accesses being available, as described above.-   6. The ASS function in the UE activates the new access.-   7. A successful response message is sent to the P-CSCF via the ASS    and the Rx1 reference point.-   8. A SIP message 200 OK is forwarded to the UE from the P-CSCF.-   9. The IMS function in the UE will, based on info from the ASS    function in the UE, move the session to the access A by sending a    SIP REINVITE message to the P-CSCF with the SDP for the access A in    order to confirm that the change to the access A has been performed.-   10. A SIP REINVITE message is forwarded to the other end of the    end-to-end SIP session via the PDN.-   11,12. A SIP 200 OK message is received from the other end of the    end-to-end session via the PDN and forwarded to the P-CSCF and the    UE.

Media transfer can now start on the new access A.

The two examples in FIGS. 8 and 9 illustrate the principle of theinvention with an IMS signalling procedure in its simplest form usingthe Rx1 reference point. Other variations of the signalling proceduresare of course possible within the scope of the invention e.g. when thecommunication nodes are integrated in other combinations or when the Rx1reference point is not used, but information instead is communicatedfrom the P-CSCF via the Rx reference point, the PCRF and the Rx2reference point to the ASS. The different integration combinations ofnodes and the ASS and the Rx2 reference point is described above.

FIG. 7 shows one example of an IP-CAN establishment according to oneembodiment of the invention. Within the scope of the invention there canalso be variations of the IP-CAN establishment, e.g. when the PCRF A andthe PCRF B are in the same node.

The ASS software comprises rules and algorithms for signalling diagramsand signalling procedures. The ASS software is arranged to performhandling of a single access or multiple accesses in parallel and guidingthe UE in activating, modifying or changing an access in order torequest the correct Radio Access Technology (RAT).

FIG. 10 schematically illustrates a method for the ASS as describedabove. The method advantageously gives the ASS the possibility to alloweach UE to have multiple accesses to at least one Packet Data NetworkGateway (PDN GW) being part of the communication network, each accesscomprising one IP-session. This is achieved by the method beingperformed as described in boxes 1001-1003.

Box 1001: The ASS collects information through interactions with thecommunication nodes and the UE.

Box 1002: The ASS stores information of all accesses for each UE in thecommunication network and information of overall load status of thecommunication network in the storing means.

Box 1003: The ASS sends control messages, based on the storedinformation, from the ASS to the UE, thereby enabling control ofmultiple UE-accesses from the ASS.

This is one embodiment of performing the method according to theinvention. Variations of this embodiment, as e.g. different orders ofperforming the steps, are possible within the scope of the appendedclaims.

The invention also includes a communication system comprising the ASS.The communication system can also include a Subscription ProfileRepository (SPR) connected to the PCRF through a reference point Sp,208.

Future revisions of specifications and standards mentioned in thedescription and claims as well as future specifications and standardsbased on these specification and standards are within the scope of theinvention.

The invention is not limited to the embodiments above, but may varyfreely within the scope of the appended claims.

1. An Access Selection Server (ASS) (201, 301, 404, 409, 603, 706, 802,902) comprising storing means and software, the ASS being adapted forlocation in a communication network comprising at least one UserEquipment (UE) (212, 302, 701, 801, 901) and communication nodes (204,401, 406, 206, 407, 601, 602, 704, 705, 211, 202) characterized by theASS being arranged to allow each UE to have multiple accesses to atleast one Packet Data Network Gateway (PDN GW) (211) being part of thecommunication network, each access comprising one IP-session (502, 503),the ASS (201, 301, 404, 409, 603, 706, 802, 902) further being arrangedto store information of all accesses for each UE (212, 302, 701, 801,901) in the communication network and information of overall load statusof the communication network in the storing means by means of collectinginformation through interactions with the communication nodes (204, 401,406, 206, 407, 601, 602, 704, 705, 211, 202), the UE and an AccessSelection Server subscriber Data Base (ASS DB) (203), and that the ASSis arranged to communicate control messages, based on the storedinformation, from the ASS to the UE, thereby enabling control ofmultiple UE-accesses from the ASS.
 2. An ASS according to claim 1,characterized in that the communication network is according to 3^(rd)Generation Partnership Project (3GPP) or a communication network beingbased on and /or evolved from 3^(rd) Generation Partnership Project(3GPP).
 3. An ASS according to claim 1-2, characterized in that saidcommunication nodes comprise at least one of an Application Function(AF) (204, 401, 406), a Policy and Charging Rules Functions (PCRF) (206,407, 601, 602, 704, 705), a Packet Data Network Gateway (PDN GW) (211)and a Network Management System (NMS) (202).
 4. An ASS according to anyone of claims 1-3, characterized in that the access from the UE to onePDN GW (211) is arranged through one or several Internet ProtocolConnectivity Access Networks (IP-CANS) (213) such as a network based ona Radio Access Technology (RAT), the UE also being arranged tocommunicate with more than one PDN GW, each PDN GW having one or severalIP-CAN connections with the UE and further that the ASS (201, 301, 404,409, 603, 706, 802, 902) is arranged to be connected to the UE (212,302, 701, 801, 901) through an IP-based interface (214, 305).
 5. An ASSaccording to any one of claims 3-4, characterized in that the ASS (201,301, 404, 409, 603, 706, 802, 902) is a separate node.
 6. An ASSaccording to claim 5, characterized in that a reference point Rx1 (215),being an Rx-reference point between the ASS (201, 301, 404, 409, 603,706, 802, 902) and the AF (204, 401, 406) and arranged to enable the AFto communicate a request, for updating the multi-access policy rules inthe UE due to AF session establishment/modification/deactivation, to theASS, and further arranged to handle communication between the ASS andthe AF for informing the ASS of activations and modifications ofIP-sessions.
 7. An ASS according to claim 6, characterized in that theAF (204, 401, 406) comprises a Proxy-Call Session Control Function(P-CSCF) (803, 903) being modified to communicate a request to the ASS(201, 301, 404, 409, 603, 706, 802, 902) for activation of accessselection.
 8. An ASS according to any one of the preceding claims 5-7,characterized in that a reference point Rx2 (216, 605), being an Rx orGx reference point or an aggregation of an Rx-reference point (205) anda Gx-reference point (209), is arranged to handle communication betweenthe ASS (201, 301, 404, 409, 603, 706, 802, 902) and the PCRF (206, 407,601, 602, 704, 705) and for transfer of information concerningIP-sessions in the PCRF to the ASS.
 9. An ASS according to any one ofthe preceding claims 5-8, characterized in that the PCRF (206, 407, 601,602, 704, 705) is extended by procedures for two new messages, the PCRFbeing arranged to report session information, via the reference pointRx2 (216, 605), to the ASS (201, 301, 404, 409, 603, 706, 802, 902)about Radio Access Technology and IP address and other possible sessioninformation stored in the PCRF session data base in the first messageand in the second message the PCRF is arranged to receiveacknowledgement from the ASS of the activation, modification anddeactivation of all UE IP-CANS.
 10. An ASS according to any one of theclaims 3-4, characterized in that the ASS (201, 301, 404, 409, 603, 706,802, 902) is a separate node or said ASS and the PCRF node (206, 407,601, 602, 704, 705) are arranged to be integrated into one logical nodeor said ASS, said PCRF and the AF (204, 401, 406) are arranged to beintegrated into one logical node.
 11. An ASS according to claim 10,characterized in that a reference point Rx2 (216, 605), being an Rx orGx reference point or an aggregation of an Rx-reference point (205) anda Gx-reference point (209), is arranged to handle communication betweenthe ASS (201, 301, 404, 409, 603, 706, 802, 902) and the PCRF (206, 407,601, 602, 704, 705) and for transfer of information concerningIP-sessions in the PCRF to the ASS and the reference point Rx2 beingfurther arranged to enable the AF to communicate a request, for updatingthe multi-access policy rules in the UE due to AF sessionestablishment/modification/deactivation, to the ASS via the Rx referencepoint and the PCRF and to handle communication between the AF and theASS via the Rx reference point and the PCRF.
 12. An ASS according to anyone of the claims 10-11, characterized in that the PCRF (206, 407, 601,602, 704, 705) is arranged to be extended by procedures for two newmessages, the PCRF being arranged to report session information, via thereference point Rx2 (216, 605), to the ASS (201, 301, 404, 409, 603,706, 802, 902) about Radio Access Technology and IP address and otherpossible session information stored in the PCRF session data base in thefirst message and in the second message the PCRF is arranged to receiveacknowledgement from the ASS of the activation, modification anddeactivation of all UE IP-CANS and the PCRF further being arranged to beextended to communicate a request for updating the multi-access policyrules in the UE due to AF sessionestablishment/modification/deactivation, from the AF to the ASS throughthe Rx2 reference point.
 13. An ASS according to any one of thepreceding claims 3-12, characterized in that the ASS (201, 301, 404,409, 603, 706, 802, 902) is arranged to receive information about loadstatus for different Radio Access Technologies within the communicationnetwork from the Network Management System (NMS) (202) through amanagement interface (218).
 14. An ASS according to any one of thepreceding claims, characterized in that the ASS software is arranged toperform the following steps: handling a single access or multipleaccesses in parallel guiding the UE in activating, modifying or changingan access in order to request the correct Radio Access Technology (RAT).15. An ASS according to any one of the preceding claims, characterizedin that the ASS software comprises access selection criteria beingarranged to be communicated to the UE (212, 302, 701, 801, 901) throughthe IP-based interface (214, 305), thus establishing a control of the UEfrom the ASS (201, 301, 404, 409, 603, 706, 802, 902).
 16. An ASSaccording to claim 15, characterized in that the access selectioncriteria is a direct instruction (303) to the UE (212, 302, 701, 801,901) to use a certain Radio Access Technology (RAT) or a preference listof available Radio Access Technologies for different services (304)arranged to instruct the UE (212, 302, 701, 801, 901) which RAT to usedepending on parameters such as location, time of the day and loadstatus.
 17. An ASS according to any one of the preceding claims,characterized in that the PDN GW (211) is a Gateway GPRS Support Node(GGSN).
 18. An ASS according to any one of the preceding claims,characterized in that there is at least one ASS (201, 301, 404, 409,603, 706, 802, 902) per Public Land Mobile Network (PLMN).
 19. A methodfor an Access Selection Server (ASS) (201, 301, 404, 409, 603, 706, 802,902) comprising storing means and software, the ASS being located in acommunication network, the communication network comprising at least oneUser Equipment (UE) (212, 302, 701, 801, 901) and communication nodes(204, 401, 406, 206, 407, 601, 602, 704, 705, 211, 202) characterized bythe ASS allowing each UE to have multiple accesses to at least onePacket Data Network Gateway (PDN GW) (211) being part of thecommunication network, each access comprising one IP-session (502, 503),the ASS (201, 301, 404, 409, 603, 706, 802, 902) further storinginformation (1002) of all accesses for each UE (212, 302, 701, 801, 901)in the communication network and information of overall load status ofthe communication network in the storing means by collecting information(1001) through interactions (1001) with the communication nodes (204,401, 406, 206, 407, 601, 602, 704, 705, 211, 202), the UE and an AccessSelection Server subscriber Data Base (ASS DB) (203) and that the ASScommunicates control messages (1003), based on the stored information,from the ASS to the UE, thereby enabling control (1003) of multipleUE-accesses from the ASS.
 20. A method according to claim 19,characterized in that the communication network is according to 3^(rd)Generation Partnership Project (3GPP) or a communication network beingbased on and/or evolved from 3^(rd) Generation Partnership Project(3GPP).
 21. A method according to claim 19-20, characterized in that thesaid communication nodes comprise at least an Application Function (AF)(204, 401, 406), a Policy and Charging Rules Functions (PCRF) (206, 407,601, 602, 704, 705), a Packet Data Network Gateway (PDN GW) (211) and aNetwork Management System (NMS) (202).
 22. A method according to any oneof claims 19-21, characterized in that the access from the UE to one PDNGW (211) runs through one or several Internet Protocol ConnectivityAccess Networks (IP-CANS) (213) such as a network based on a RadioAccess Technology (RAT), the UE also communicating with more than onePDN GW, each PDN GW having one or several IP-CAN connections with the UEand further that the ASS (201, 301, 404, 409, 603, 706, 802, 902) isconnected to the UE (212, 302, 701, 801, 901) through an IP-basedinterface (214, 305).
 23. A method according to any one of claims 21-22,characterized in that the ASS (201, 301, 404, 409, 603, 706, 802, 902)is a separate node.
 24. A method according to claim 23, characterized inthat a reference point Rx1 (215), being an Rx-reference point betweenthe ASS (201, 301, 404, 409, 603, 706, 802, 902) and the AF (204, 401,406) enabling the AF to communicate a request, for updating themulti-access policy rules in the UE due to AF sessionestablishment/modification/deactivation, to the ASS, and further tohandle communication between the ASS and the AF for informing the ASS ofactivations and modifications of IP-sessions.
 25. A method according toclaim 24, characterized in that the AF (204, 401, 406) comprises aProxy-Call Session Control Function (P-CSCF) (803, 903) being modifiedto communicate a request to the ASS (201, 301, 404, 409, 603, 706, 802,902) for activation of access selection.
 26. A method according to anyone of the preceding claims 23-25, characterized in that a referencepoint Rx2 (216, 605), being an Rx or Gx reference point or anaggregation of an Rx-reference point (205) and a Gx-reference point(209), is used to handle communication between the ASS (201, 301, 404,409, 603, 706, 802, 902) and the PCRF (206, 407, 601, 602, 704, 705) andfor transfer of information concerning IP-sessions in the PCRF to theASS.
 27. A method according to any one of the preceding claims 23-26,characterized in that the PCRF (206, 407, 601, 602, 704, 705) isextended by procedures for two new messages, the PCRF reports sessioninformation, via the reference point Rx2 (216, 605), to the ASS (201,301, 404, 409, 603, 706, 802, 902) about Radio Access Technology and IPaddress and other possible session information stored in the PCRFsession data base in the first message and in the second message thePCRF receives acknowledgement from the ASS of the activation,modification and deactivation of all UE IP-CANS.
 28. A method accordingto any one of the claims 21-22, characterized in that the ASS (201, 301,404, 409, 603, 706, 802, 902) is a separate node or said ASS and thePCRF node (206, 407, 601, 602, 704, 705) are integrated into one logicalnode or said ASS, said PCRF and the AF (204, 401, 406) are integratedinto one logical node.
 29. A method according to claim 28, characterizedin that a reference point Rx2 (216, 605), being an Rx or Gx referencepoint or an aggregation of an Rx-reference point (205) and aGx-reference point (209), handles communication between the ASS (201,301, 404, 409, 603, 706, 802, 902) and the PCRF (206, 407, 601, 602,704, 705) and transfers information concerning IP-sessions in the PCRFto the ASS and the reference point Rx2 further enabling the AF tocommunicate a request, for updating the multi-access policy rules in theUE due to AF session establishment/modification/deactivation, to the ASSvia the Rx reference point and the PCRF and further handlescommunication between the AF and the ASS via the Rx reference point andthe PCRF.
 30. A method according to any one of the claims 28-29,characterized in that the PCRF (206, 407, 601, 602, 704, 705) isextended by procedures for two new messages, the PCRF reports sessioninformation, via the reference point Rx2 (216, 605), to the ASS (201,301, 404, 409, 603, 706, 802, 902) about Radio Access Technology and IPaddress and other possible session information stored in the PCRFsession data base in the first message and in the second message thePCRF receives acknowledgement from the ASS of the activation,modification and deactivation of all UE IP-CANS and the PCRF furtherbeing extended to communicate a request, for updating the multi-accesspolicy rules in the UE due to AF sessionestablishment/modification/deactivation, from the AF to the ASS throughthe Rx2 reference point.
 31. A method according to any one of thepreceding claims 21-30, characterized in that the ASS (201, 301, 404,409, 603, 706, 802, 902) receives information about load status fordifferent Radio Access Technologies within the communication networkfrom the Network Management System (NMS) (202) through a managementinterface (218).
 32. A method according to any one of the precedingclaims 19-31, characterized in that the ASS software performs thefollowing steps: handling a single access or multiple accesses inparallel guiding the UE in activating, modifying or changing an accessin order to request the correct Radio Access Technology (RAT).
 33. Amethod according to any one of the preceding claims 19-32, characterizedin that the ASS software comprises access selection criteria beingcommunicated to the UE (212, 302, 701, 801, 901) through the IP-basedinterface (214, 305), thus establishing a control of the UE from the ASS(201, 301, 404, 409, 603, 706, 802, 902).
 34. A method according toclaim 33, characterized in that the access selection criteria is adirect instruction (303) to the UE (212, 302, 701, 801, 901) to use acertain Radio Access Technology (RAT) or a preference list of availableRadio Access Technologies for different services (304) instructing theUE (212, 302, 701, 801, 901) which RAT to use depending on parameterssuch as location, time of the day and load status.
 35. A methodaccording to any one of the preceding claims 19-34, characterized inthat the PDN GW (211) is a Gateway GPRS Support Node (GGSN).
 36. Amethod according to any one of the preceding claims 19-35, characterizedin that there is at least one ASS (201, 301, 404, 409, 603, 706, 802,902) per Public Land Mobile Network (PLMN).
 37. A User Equipment (UE)(212, 302, 701, 801, 901) arranged to interact with a communicationnetwork, characterized in that the UE comprises an ASS-function whereinthe UE further is arranged to communicate through an IP-based interface(214, 305) with an ASS (201, 301, 404, 409, 603, 706, 802, 902), the ASSfunction in the UE being arranged to handle requests from the ASS toperform activation of new accesses and/or modification or deactivationof existing accesses.
 38. A User equipment according to claim 37,characterized by the ASS function in the UE being adapted for one ormore of: informing the ASS about available passive accesses for the UEand/or geographical location information for the UE. receiving dataconcerning selection of a Radio Access Technology communicating arequest for an IP-CAN establishment initiating for SIP invite/reinvite.39. A communication system comprising an ASS according to any of claims1-18.
 40. A communication system according to claim 39, characterized byfurther comprising a Subscription Profile Repository (SPR) (207)connected to the PCRF (206, 407, 601, 602, 704, 705) through a referencepoint Sp (208) or integrated with other communication nodes.